To provide a method of promoting quality of crystals and increasing growth rate in a process of carrying out crystal growth in a horizontal direction of an amorphous silicon film by using a catalyst element expediting crystallization, in respect of the amorphous silicon film for carrying out horizontal growth by using a catalyst element of nickel or the like, irregularities of a matrix (underlayer film or substrate) in contact with the amorphous silicon film are made smaller than the film thickness of the amorphous silicon film by which crystal growth occurs substantially entirely by the catalyst element and interruption of growth caused by natural crystallization or the irregularities of a matrix can be prevented.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of forming a crystalline semiconductor film comprising silicon for crystallizing an amorphous semiconductor film comprising silicon formed over a substrate by a horizontal growth process using a catalyst element promoting to crystallize the amorphous semiconductor film at an annealing temperature T o , wherein a density of projections present at an underlayer film or the substrate in contact with a bottom face of the amorphous semiconductor film has a value specified below or lower; g ( T, f ( T 0 )) 2 wherein a relationship specified below is established between the annealing temperature and an annealing time period when the amorphous semiconductor film is formed on the substrate by the same process and the amorphous semiconductor film naturally starts crystallizing; t f ( T ) ( T ; annealing temperature, t ; annealing time period) wherein a relationship specified below is established between the annealing temperature and a growth distance in the using the catalyst element promoting to crystallize the amorphous semiconductor film in respect of the amorphous semiconductor film formed on the substrate; X g ( T, t ) ( x ; growth distance).
2. A method according to claim 1 , wherein the catalyst element is constituted by a single or a plurality of kinds of elements selected from the group consisting of Ni, Pd, Pt, Cu Ag and Fe.
3. A method of manufacturing a semiconductor device comprising the steps of: polishing a surface over a substrate; forming an insulating film comprising silicon oxide over the polished substrate; forming a semiconductor film comprising amorphous silicon over said insulating film; crystallizing the semiconductor film by heating; and patterning the crystallized semiconductor film to form an active layer, wherein the surface over said substrate is polished so that a root mean square of a surface roughness of said surfaces is smaller than a thickness of the semiconductor film and a density of projection on said surface is 100 pieces/cm 2 or less.
4. A method of manufacturing a semiconductor device comprising the steps of: polishing a surface over a substrate; forming an insulating film comprising silicon oxide over the polished substrate; forming a semiconductor film comprising amorphous silicon over said insulating film; providing a selected portion of said semiconductor film with a crystallization promoting; material; crystallizing the semiconductor film by heating wherein crystals grow from said selected portion to a region adjacent to said selected portion; and patterning the crystallized semiconductor film to form an active layer, wherein the surface over said substrate is polished so that a toot mean square of a surface roughness of said surfaces is smaller than a thickness of the semiconductor film.
5. The method according to claim 4 wherein said crystallization promoting material comprises a metal selected from the group consisting of Ni, Pd, Pt, Cu, Ag and Fe.
6. A method of manufacturing a semiconductor device comprising the steps of: forming a semiconductor film comprising amorphous silicon on an insulating surface; providing a selected portion of said semiconductor film with a crystallization promoting material; crystallizing the semiconductor film by heating at a temperature T 0 , wherein crystals grow from said selected portion to a region adjacent to said selected portion; and patterning the crystallized semiconductor film to form an active layer of a thin film transistor, wherein a density of projections present at the insulating surface has a value specified below or lower; g ( T, f (T 0 )) 1 wherein a relationship specified below is established between the heating temperature and a heating; time period when the semiconductor film is formed on the insulating surface by the same process and the semiconductor film naturally starts crystallizing; t f ( T ) ( T ; annealing temperature t; annealing time period) wherein a relationship specified below is established between the heating temperature and a growth distance from said selected portion to a region adjacent to said selected portion to crystallize the semiconductor film in respect of the semiconductor film formed on the insulating surface: X g ( T,t ) X growth e ( T, t ) distance.
7. The method of claim 6 wherein said crystallization promoting material comprises a metal selected from the group consisting of Ni, Pd, Pt, Cu, Ag and Fe.
8. A method of manufacturing a Semiconductor device comprising the steps of: polishing a surface of an insulating surface; forming a semiconductor film comprising amorphous silicon on the insulating surface by a film formation method; providing a selected portion of said semiconductor film with a crystallization promoting material; crystallizing the semiconductor film by heating at a temperature T 0 , wherein crystals grow from said selected portion to a region adjacent to said selected portion; and patterning the crystallized semiconductor film to form an active layer of a thin film transistor, wherein a density of projections present at the insulating surface has a value specified below or loser; g ( T,f ( T 0 )) 1 wherein a relationship specified below is established between the heating temperature and a heating time period when the semiconductor film is formed on the insulating surface by said film formation method and the semiconductor film naturally starts crystallizing; t f ( T ) ( T ; annealing temperature, t; annealing time period) wherein a relationship specified below is established between the heating temperature and a growth distance from said selected portion to a region adjacent to said selected portion to crystallize the semiconductor film in respect of the semiconductor film formed on the insulating surface: X g ( T, t ) ( x ; growth distance).
9. The method according to claim 8 wherein said crystallization promoting material comprises a metal selected from the group consisting of Si, Pd, Pt, Cu, Ag and Fe.
10. A method of manufacturing a semiconductor device comprising the steps of: polishing a surface of an insulating surface; forming a semiconductor film comprising amorphous silicon on the insulating surface by a film formation method; crystallizing the semiconductor film by horizontal growth process to crystallize the semiconductor film at a heating temperature T 0 ; and patterning the crystallized semiconductor film to form an active layer of a thin film transistor, wherein a density of projections present at the insulating surface has a value specified below or lower; g ( T, f ( T 0 )) 2 wherein a relationship specified below is established between the heating temperature and a heating time period when the semiconductor film is formed on the insulating surface by said film formation method and the semiconductor film naturally starts crystallizing; t f ( T ) ( T ; annealing temperature, t ; annealing time period) wherein a relationship specified below is established between the heating temperature and a growth distance in the horizontal growth; X g ( T, t ) ( x ; growth distance).
11. A method of manufacturing a semiconductor device comprising the steps of: polishing a surface over a substrate; forming a semiconductor film comprising amorphous silicon over the polishing substrate; providing a solution comprising a metal containing material for promoting crystallization of the semiconductor film over said semiconductor film; crystallizing the semiconductor film by heating; and patterning the crystallized semiconductor film to form an active layer, wherein the surface over said substrate is polished so that a root mean square of a surface roughness of said surfaces is smaller than a thickness of the semiconductor film and a density of projection on said surface is 100 pieces/cm 2 or less.
12. A method of manufacturing a semiconductor device comprising the steps of: polishing a surface over a substrate; forming a semiconductor film comprising amorphous silicon over the polishing substrate; providing a solution comprising a metal containing material for promoting crystallization of the semiconductor film over said semiconductor film; crystallizing the semiconductor film by heating wherein crystals grow from said selected portion to a region adjacent to said selected portion; and patterning the crystallized semiconductor film to form an active layer; wherein the surface over said substrate is polished so that a root mean square of a surface roughness of said surfaces is smaller than a thickness of the semiconductor film.
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December 22, 1997
May 11, 2004
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